Sevrsky BT-8

The Seversky BT-8 was a monoplane Basic Trainer with seating for an instructor and trainee, under a greenhouse canopy, and had fixed landing gear.  Per Reference [8] only 30 of this type aircraft were orddered in 1935 but they were quickly supplanted by the North American BT-9 as a USAAC Basic Trainer.  However, Reference [8] does notes that one of these type aircraft was used for use by the Chief of the Air Corps as a transport in 1936.

As shown in the images below distinguishing features of this aircraft including;

• radial engine
  
• inline cockpits for the instructor and trainee under a greenhouse canopy
• low mounted wing
• heavily spatted fixed landing gear
  

[Image Sources: US Government/Public Domain via Ref [8] - as annotated by this site]

        [Source: Ref [14a] - US Government/Public Domain]

In order to try and better develop weight estimating relationships an effort has been made to estimate the length of the fuselage aft of the firewall, and the length of the engine section forward of the firewall based off scaled drawings.  Together these two distances add to a term called the "structural length" and do not consider any portion of the engine or propeller shaft the extend foward of the fuselage/cowling, or any empennage that extends aft of the fuselage structure.  The drawing below shows the current best estimate of these dimensions obtained from available drawings of the airplane and will be updated with any real world data that becomes available.  For any aircraft with an inclined firewall, an attempt has been made to locate an approximate center of this location.


                                                                    Source References [2] [3] & [8]

In the above images, dimensions in Black come from the source material while dimesions in Red have been approximated from the data available.

The table below summarizes the current data collected on this type aircraft, identifying sources for the data

		Seversky	Secondary Sources	Notes
		BT-8
Primary Source		2
No of Crew		2
Engine:
Qty		1	5
Model		R-985-11	5
Displacement	(cu in)	985	5
Power
Military	(HP)
War Emergency	(HP)
Normal	(HP)	440	5
Take Off	(HP)	440	5
Eng Dims
Length	(ft)
Width/Dia	(ft)
Height	(ft)
Base Engine Wt	(lb)
Propeller
# Blades		2
Dia	(ft)	8.5
Manufacturer
Type
Wing
Span	(ft)
Root Thickness	(%)
	(in)
Total Area	(sq ft)	220
Wing (less Ailerons & Flaps)	(sq ft)
Ailerons	(sq ft)
Flaps	(sq ft)
Tail Area	(sq ft)
V Tail Area	(sq ft)
Fin	(sq ft)
Rudder	(sq ft)
H Tail Area	(sq ft)
Stabilizer	(sq ft)
Elevator	(sq ft)
Total Control Surf Area	(sq ft)
Length
Overall	(ft)
Fuselage	(ft)	24.3
Body	(ft)
Body Depth	(ft)
Body Width	(ft)
Fuel Tank Volume	(gal)
Wing Tanks	(gal)
FuselageTanks	(gal)
Oil Tank Volume	(gal)
Water Injection Fluid Tank Volume	(gal)
Wetted Area (sqf)	(sq ft)
Pwr Ldng	(lb/HP)	9.37
Wing Ldng	(lb/sq ft)	18.75
Struct. Des. GW	(lb)
Ultimate Load Factor	(G's)
Design Speed	(mph)	175
Not to Exceed Speed	(mph)
Total Struct Weight		1434
Total Wing		610
Wing
Ailerons
Flaps
Fuselage Carry-Through
Tail		71
H Tail		58
Stabilizer
Elevator
V Tail		13
Fin
Rudder
Body + Eng Section + LG
Body + LG		753
Body		433
Fuselage
Engine Section
Landing Gear		320
Mn Landing Gr		298
Tail/Nose Aux LG		22
Tail Hook
Booms
Nacelles
Total Propulsion Weight		895
Engine w/ Accessories		691
Engine(s) as Installed		628
Accessories		63
Turbocharger(s)
Controls		12
Propeller(s)		105
2-Blade		105
3-Blade
4-Blade
Starting System		37
Water Injection System
Tanks
Piping Etc
Cooling System
Lube System		21
Tanks
Piping Etc
Fuel System		29
Tanks
Piping Etc
Total Sys. & Eqpmt.		688
Instruments		68
Surface Controls		123
Hydraulics
Electrical Equip		165
Electronics (Purple means incl in Furn/Gray in Useful Ld)
Arm Prov/Equipment & Armor
Furnishings		332
Anti-Ice (If not in Furn)
Other /Misc
Hoisting Gear
Floatation Gear
Armor Plate
Empty Wt		3017
Basic Mission Useful Load		1107
Crew		400
Equipment
Oil		68
Fuel		600
Fuel & Oil Trapped in Systems
Water Solution for Engine Injection
Bombs/Torp Etc
Radio (if Not Included in Empty Wt)
Nav Equipment
Oxygen System
Armament
Guns & Ammo
Guns
Ammo
Pyrotechnics
Camera
Other
Other Useful Load		39
Basic Mission GW		4124

Notes: This website has been developed with a number of low cost or free programs including Hot Metal Pro, KompoZer, MicroSoft Designer and Da Button Factory.com

Rev 4-12-26

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